Two-wheeled handtrucks are commonly utilized for moving loads which are too heavy or bulky to be moved by a single person. Handtrucks typically include a horizontal load plate, a pair of side rails extending vertically upward from the load plate, and a pair of wheels. An operator places a load on the load plate and pivots the handtruck so that it rests only on its wheels, the load plate is not in contact with the ground. With the handtruck in this position, a heavy load may be easily moved. To unload the handtruck an, operator will pull or twist the handtruck from under the load while tipping the load slightly forward. In most applications, an operator will repeatedly load and unload a handtruck to accomplish a series of tasks, such as making deliveries or moving industrial supplies. To reduce the potential for injury to the operator and damages to the load from falling forward off the handtruck, many prior art handtrucks are equipped with various mechanisms which assist removal of the load from the handtruck.
Many prior art devices push the load off the handtruck using a bar or plate which is suspended from a point above the load and pivoted outwardly against the load to remove the load from the handtruck. In particular, U.S. Pat. No. 3,878,958 to Ring discloses a two-wheeled handtruck with a back plate which is swingably supported from a point near the upper ends of the truck handles. A handle acts on a linkage attached to the backplate to move the back plate arcuately forward, thus pushing the load off the front of the handtruck. The Ring device results in force being applied to the load in an arcuately upward fashion, tending to tip the load forward. Additionally, the friction between the plate and load as the plate moves arcuately upward against the load also tends to tip the load forward, resulting in damage to the load.
U.S. Pat. No. 3,844,431 to Crawford discloses an unloader mechanism for a handtruck which attempts to improve upon the prior art by avoiding the arcuate motion of other load removal mechanisms. Unfortunately, the Crawford mechanism is designed solely for foot operation by a user. This method of operation requires the user to be off-balance while attempting to unload the handtruck. To reduce the potential for injury or accident, the operator of any such handtruck should be standing securely with the operator's weight balanced on both feet.
U.S. Pat. No. 5,290,051 to Olson also discloses an unloading mechanism for two-wheeled handtrucks. In the Olson device, an operator grasps a handle and moves the handle slidably and pivotably downward. The handle is mechanically linked to a push-off shoe which pushes the load off the handtruck. While the Olson device avoids most of the arcuate motion of prior art devices, the operator must slide the handle downwardly through a sliding track while also pivoting the handle, a motion which is more difficult for the operator to perform than a simple pivoting motion. The Olson device also requires additional sliding elements which unnecessarily complicate the unloading mechanism. Thus, there remains a need for a simple, hand operable unloading mechanism for a two-wheeled handtruck having simple, uncomplicated linkages which enable a load to be moved substantially horizontally off a handtruck.